Diabetic retinopathy is the world's top cause of visual impairment among working adults, and studies have predicted that the number of adult type 2 diabetes patients will increase internationally, but mainly in Asia.
This in turn means more Asians will be affected by diabetic retinopathy, necessitating effective strategies to prevent or at least delay the condition.
Recent research has found positive associations between fish intake and diabetic retinopathy in several ethnic groups.
However, no such study has been conducted on Asian populations, whose dietary patterns, as well as diabetes and diabetic retinopathy burden, differ from that of Western populations.
As such, researchers at the Singapore National Eye Centre, National University of Singapore, A*STAR, Nanyang Technological University and Medical University of Vienna conducted a cross-sectional study to assess the link between dietary fish intake and the severity of diabetic retinopathy and retinal vascular calibre in Asian type 2 diabetes patients.
They recruited 357 subjects with a median age of 58 years (31% of which were women) from a tertiary eye care institution in Singapore and evaluated their fish intake via a validated food frequency questionnaire. Their diabetic retinopathy severity and retinal vascular calibre was assessed using digital retinal photographs.
The researchers then observed that greater fish consumption was significantly associated with lower odds of severe diabetic retinopathy.
For the subjects without diabetic retinopathy, those who ate the most fish had a wider retinal arteriolar and venular vascular calibre than those who ate the least fish.
In addition, those who ate more fish had a lower risk of severe diabetic retinopathy, and in diabetics without retinopathy, higher fish intake was linked to wider retinal vascular calibre.
However, the researchers also said more studies were required to "reinforce the direction of the causality".
They wrote that their findings were consistent with previous studies on other ethnic groups, but that the precise mechanism behind the association between dietary fish intake and diabetic retinopathy was still unclear.
In conclusion, they wrote: "Our data indicate a complex relationship among dietary fish intake, retinal vascular calibre, and severity of diabetic retinopathy.
"Future studies are required to draw more definitive inferences on the direction of causality."
Source: Scientific Reports
"The relationship of dietary fsh intake to diabetic retinopathy and retinal vascular caliber in patients with type 2 diabetes"
Authors: Jacqueline Chua, et al.